1. Field of the Invention
This invention relates to railway wagon retarders, and in particular railway wagon retarders having the capability of retarding or boosting the speed of a wagon passing along a railway track.
2. Description of the Prior Art
One form of railway retarder/booster device is illustrated in UK Patent No. 1462045 corresponding to U.S. Patent application No. 447,004 filed Feb. 28 1974, now abandoned. In the device described in this patent the speed boosting capability of the device is achieved using a pneumatic arrangement which operates a speed booster unit separate from the usual retarder unit. The air supply provided to the device in order to facilitate the pneumatic arrangement is common to a number of devices and is not distinct to one particular device. Therefore there are a number of air supply lines to these devices distributed over the marshalling yard.
Now, in certain countries the operating conditions, i.e. the maintenance of the installed devices, land conditions, etc., are not favourable for the maximum efficiency of operation of such retarding devices. In fact a particular source of trouble has been shown to be the air supply lines which can fail in operation. Such devices need a regular maintenance program paying particular attention to the air supply lines.
The present invention is concerned with providing an alternative type of railway wagon retarder having a speed boosting capability.